<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: PregReplace.php 16217 2009-06-21 19:39:00Z thomas $
 */

/**
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Filter_PregReplace implements Zend_Filter_Interface
{
	/**
	 * Pattern to match
	 * @var mixed
	 */
	protected $_matchPattern = null;

	/**
	 * Replacement pattern
	 * @var mixed
	 */
	protected $_replacement = '';

	/**
	 * Is unicode enabled?
	 *
	 * @var bool
	 */
	static protected $_unicodeSupportEnabled = null;

	/**
	 * Is Unicode Support Enabled Utility function
	 *
	 * @return bool
	 */
	static public function isUnicodeSupportEnabled()
	{
		if (self::$_unicodeSupportEnabled === null) {
			self::_determineUnicodeSupport();
		}

		return self::$_unicodeSupportEnabled;
	}

	/**
	 * Method to cache the regex needed to determine if unicode support is available
	 *
	 * @return bool
	 */
	static protected function _determineUnicodeSupport()
	{
		self::$_unicodeSupportEnabled = (@preg_match('/\pL/u', 'a')) ? true : false;
	}

	/**
	 * Constructor
	 *
	 * @param  string $match
	 * @param  string $replace
	 * @return void
	 */
	public function __construct($matchPattern = null, $replacement = null)
	{
		if ($matchPattern) {
			$this->setMatchPattern($matchPattern);
		}

		if ($replacement) {
			$this->setReplacement($replacement);
		}
	}

	/**
	 * Set the match pattern for the regex being called within filter()
	 *
	 * @param mixed $match - same as the first argument of preg_replace
	 * @return Zend_Filter_PregReplace
	 */
	public function setMatchPattern($match)
	{
		$this->_matchPattern = $match;
		return $this;
	}

	/**
	 * Get currently set match pattern
	 *
	 * @return string
	 */
	public function getMatchPattern()
	{
		return $this->_matchPattern;
	}

	/**
	 * Set the Replacement pattern/string for the preg_replace called in filter
	 *
	 * @param mixed $replacement - same as the second argument of preg_replace
	 * @return Zend_Filter_PregReplace
	 */
	public function setReplacement($replacement)
	{
		$this->_replacement = $replacement;
		return $this;
	}

	/**
	 * Get currently set replacement value
	 *
	 * @return string
	 */
	public function getReplacement()
	{
		return $this->_replacement;
	}

	/**
	 * Perform regexp replacement as filter
	 *
	 * @param  string $value
	 * @return string
	 */
	public function filter($value)
	{
		if ($this->_matchPattern == null) {
			require_once 'Zend/Filter/Exception.php';
			throw new Zend_Filter_Exception(get_class($this) . ' does not have a valid MatchPattern set.');
		}

		return preg_replace($this->_matchPattern, $this->_replacement, $value);
	}

}
